The simple answer is yes, they can. Ascaney are not both Chinese nationals they are able to legally register their marriage in Thailand.
It is a more complicated process compared to many nationalities. The process must be started well before a Chinese national who is holding a Mainland passport even comes to Thailand, unlike many nationalities. It requires first off by them to get a certified marital status document from the Chinese government in China. Then … Maybe best to contact us for the latest procedure and details on what you must prepare in China before you come to Thailand. To make it possible to register here in Thailand.
You as a Chinese citizen, at present, can not register in every city in Thailand.
To legally register your marriage under Thai law it will require more time before you come to Thailand to get all your documentation in order and translated before you even come here.
If you are working in Thailand there is a way to do all the supporting documents from her but it is even a longer process and takes even longer to get done. There is no way around this.
Chinese nationals are allowed to marry most any foreigner, not only a Chinese national, legally. So Chinese legal marriages can be registered under Thai law in only a few places in Thailand. Most registrars will do it.
If you wish to arrange your legal marriage in Thailand, please contact us through our contact page and is best to use our questionnaire for the service, as we need many details, to answer correctly.
This post is not meant to be a full detailed explanation of the process. Because this is not meant to be a DYI explanation of the entire process as that is not possible at this time. As well the process and requirements change depending on the other nationality involved. In fact, I do not recommend that any Chinese national try to do it on their own.
If you contact us, I can explain the procedure as it applies to you as a couple.